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Topics• Layered approach to computer design• Machine code example• Components of ISA• Computer implementations
– Inside a PC– IC technology and its trends– Input/output devices – Main memory– Secondary storage– Network
• IC process overview
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Transistors
Layered Approach in Computer Design
Computer Architecture orInstruction Set Architecture
Logic gates
Microarchitecture
Architecture
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Machine Code Example
swap:muli $t0, $a0, 4add $t0, $a1, $t0lw $t1, 0($t0)lw $t2, 4($t0)sw $t2, 0($t0)sw $t1, 4($t0)jr $ra
void swap(int v[], int k){
int temp;temp = v[k];v[k] = v[k+1];v[k+1] = temp;
}
00000000101000010…00000000000110000…10001100011000100…10001100111100100…10101100111100100…10101100011000100…00000011111000000…
com
piler
assemble
r
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Components of ISA
• In most cases, a “programmer’s reference manual” (PRM) will disclose the ISA of a processor
• To understand an ISA, find in PRM– Data types the processor supports– Supported instructions and their definitions– Registers (general-purpose & special purpose)– Processor modes– Exception mechanism
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Inside a PC
• Integrated Circuits (ICs)– CPU (Central Processing Unit), companion chipset, memory,
peripheral I/O chip (e.g., USB, IDE, IEEE1394, …)• Printed Circuit (PC) boards (next 2 slides)
– Substrate for ICs and interconnection– Distribution of clock, power supply– Heat dissipation
• Hard disk, CD-RW DVD-RW, (floppy disk)• Power supply• Chassis
– Holds boards, power supply, and provides physical interface for user and other systems
• Connectors and cables
9Closeup photo of one side of a motherboard PCB, showing conductive traces and solder points for through-hole components on the opposite side.
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Part of a 1983 Sinclair ZX Spectrum computer board. Populated PCB, showing conductive traces, through-hole paths onto the other surface, with some mounted electrical components
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Integrated Circuits• Primarily crystalline silicon• 1mm~25mm on a side• 100 ~ 1000M transistors• 25 ~ 250M “logic gates”• CMOS (Complementary Metal
Oxide Semiconductor) technology
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Moore’s Law• The term Moore's Law has been coined by Carver Mead around
1970.[4] Moore's original statement can be found in his publication "Cramming more components onto integrated circuits", Electronics Magazine 19 April 1965:
• “The complexity for minimum component costs has increased at a rate of roughly a factor of two per year ... Certainly over the short term this rate can be expected to continue, if not to increase. Over the longer term, the rate of increase is a bit more uncertain, although there is no reason to believe it will not remain nearly constant for at least 10 years. That means by 1975, the number of components per integrated circuit for minimum cost will be 65,000. I believe that such a large circuit can be built on a single wafer.[1]
• Astounding that it has held for so long!!!
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Memory Capacity Trend (DRAM)
1.4x/year or 2x every 2 years8000x since 1980!
size
Year
Bit
s
1000
10000
100000
1000000
10000000
100000000
1000000000
1970 1975 1980 1985 1990 1995 2000
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Technology Advances (!)
• Memory– DRAM capacity: 2x / 2 years (since ’96)– 64x size improvement in last decade
• Processor– Speed (in terms of clock frequency): 2x / 1.5 years (since
’85)– 100x performance improvement in last decade
• Disk– Capacity: 2x / 1 year (since ’97)– 250x size improvement in last decade
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Your PC After Graduation
• Processor speed– 6~8GHz
• Memory capacity– 4GB~8GB
• Disk capacity– 1000GB or 1TB
• New units: Mega to Giga, Giga to Tera, (Tera to Peta, Peta to Exa, Exa to Zetta, Zetta to Yotta)– What is kilo, mea, giga, tera, peta, and all that?
• New, faster serial interfaces for various peripherals
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A PC in the mid 90s• IBM PC AT
– Based on 80286 (80586 is Pentium-1)
• Processor speed– 20MHz (?) compared to 5,000MHz
• Memory capacity– 1MB compared to 4000MB
• Disk capacity– 40MB compared to 1000GB
• No CD-ROM!
• 14 inch monitor (not flat!), VGA (640x480)
• Wheel mouse– 2 buttons
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Input Devices
• Accepts input from human (or from other machine)
• Desktop computers– Keyboard– Mouse (touchpad)– Joystick– …
• Servers– Terminals on network
• Cell phone – Embedded computers– Keypad
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Input Devices, cont’d
• Mouse– Wheel mouse (hard to find nowadays)– Optical mouse
• Takes 1,500 “photo shots” of LED reflection to detect any movement
• Keyboard or keypad– Not many changes so far
• Web camera
• Voice recognition– Partly successful
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Output Devices
• Passes information to human (or to other machine)
• Desktop computers– Display (CRT or LCD)– Sound– …
• Servers– Terminals on network
• Cell phone – Embedded computers– Screen– Sound– Vibration
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Output Devices, cont’d
• Display– CRT to LCD– LCD size from 10 inch to 24 inch
• Resolution from 640x480 to 1600x1200
• Sound– Simple “tick” to theatre-like effects
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Main memory
• PC/servers use “DRAM” (Dynamic RAM)– SDRAM– DDR SDRAM– RDRAM (RAMBUS DRAM)
A typical SDRAM “module”
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Main memory, cont’d
• Embedded computers use DRAM or SRAM (or both) depending on applications
SRAM, SDRAM, FLASH allin a same chip!
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Storage
• Secondary storage (cf. main memory)• Non-volatile• Stores programs, user-saved data, etc.
• In PC/server domain, magnetic disk (hard-disk) is usually used
• In embedded computers, “flash” memory or “ROM” is usually employed
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Computer Networks
• Local Area Network (LAN)– Within limited distance (e.g., in a building)– Mostly based on Ethernet– 10Mbps, 100Mbps, 1Gbps, 10Gbps, …
• Wide Area Network– Connecting networks far apart
• At home,– Modem: 14.4Kbps, 28.8Kbps, 33.6Kbps, 56Kbps– Cable modem/DSL: several hundred Kbps ~ several Mbps– Higher-speed DSL technologies
• Proliferation of wireless LAN (IEEE802.11)– 1 ~ 100Mbps
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(Simple) IC Process Overview
• Silicon ingot (silicon cylinder)• (Blank) Wafers• Various steps to build circuits on wafers
– Patterns of chemicals placed wafer• “Wafer test” to sort out bad parts• Tested “die” (diced into components – dies, chips)• “Packaging” steps
– Wire bonding (connected to the I/O pins of a package)• “Chip test” to sort out bad parts (mistakes happen during
packaging)• Products
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